Pair wave function symmetry in UTe 2 from zero-energy surface state visualization
- Qiangqiang Gu
- Shuqiu Wang
- Joseph P. Carroll
- Kuanysh Zhussupbekov
- Christopher Broyles
- Sheng Ran
- Nicholas P. Butch
- Jarryd A. Horn
- Shanta Saha
- Johnpierre Paglione
- Xiaolong Liu
- J. C. Séamus Davis
- Dung-Hai Lee
2025-05-29
Although nodal spin-triplet topological superconductivity appears probable in uranium ditelluride (UTe 2 ), its superconductive order parameter Δ k remains unestablished. In theory, a distinctive identifier would be the existence of a superconductive topological surface band, which could facilitate zero-energy Andreev tunneling to an s-wave superconductor and also distinguish a chiral from a nonchiral Δ k through enhanced s-wave proximity. In this study, we used s-wave superconductive scan tips and detected intense zero-energy Andreev conductance at the UTe 2 (0-11) termination surface. Imaging revealed subgap quasiparticle scattering interference signatures with a -axis orientation. The observed zero-energy Andreev peak splitting with enhanced s-wave proximity signifies that Δ k of UTe 2 is a nonchiral state: B 1 u , B 2 u , or B 3 u . However, if the quasiparticle scattering along the a axis is internodal, then a nonchiral B 3 u state is the most consistent for UTe 2 .